The present invention generally relates to the technical field of processing a food product in particular fish in a food processing unit defining an interior space having an ambient temperature and a relative humidity controllable by the food processing unit.
The state of the art food processing of a food product generally comprises a thawing step in which the food products in particular fish are submerged into pool of salt water being recirculated so as to provide a good temperature transfer between the fish and the salt water. This operation is continued until the fish temperature reaches approximately 0xc2x0 C. Next, the fish are removed from the salt water pool during a staging step and exposed to the ambient temperature initially in the range from 10xc2x0 C. to 18xc2x0 C. and slowly increasing to approximately 60xc2x0 C. Next, the fish are pre-cooked during a pre-cooking step in which the fish are exposed to an ambient temperature of approximately 100xc2x0 C. until the fish temperature reaches approximately 65xc2x0 C. Next the fish are spray cooled during a spray cooling step in which the ambient temperature is reduced from approximately 100xc2x0 C. to approximately 20xc2x0 C. by spraying the fish with cooling water until the fish reaches a temperature of approximately 50xc2x0 C. Finally, the fish are chilled during a chill conditioning step during which the ambient temperature remains in the temperature range 20xc2x0 C. to 30xc2x0 C. until the fish reaches the ambient temperature.
In the state of the art food processing techniques the entire process lasts for approximately eighteen to nineteen hours from frozen food product to treatable cooked food product. Thus the time needed for processing the food products is very long and expensive, since the product flow is determined entirely on the basis of the process. Further the food product quality during the processing is generally not continuously monitored, potentially causing non-suitable food products to complete the entire process and unnecessarily contributing to the energy consumption.
Hence the state of the art food processing techniques are accomplished without specific considerations regarding processing efficiency and quality for any particular food products. These considerations include energy consumption of the processes, food processing quality defining timing and duration of operations and food processing repeatability.
An object of the present invention is to provide an environment for thawing, cooking and cooling of a food product or food products in particular fish, which environment avoids any oxidation of the surface of the food products during the thawing, cooking and cooling.
A further object is to establish environment enabling an improved energy transfer between the food products and the environment while limiting dehydration of the food products.
An additional object is to provide a reduction of the food processing time employed in state of the art food processing methods and apparatus thus achieving a reduction of the processing time and saving working hours associated with the processing.
A particular advantage of the present invention is utilisation of heat energy by conservation or reuse of established temperatures and relative humidities during the thawing, cooking and cooling of food products.
A particular feature of the present invention is that thawing, cooking and cooling may all be implemented in one processing chamber by continuously changing the internal environment of the processing chamber or in a series of processing chambers interconnected via ports and transporting the food products from one processing chamber performing one operation to a next processing chamber performing a second operation.
Above mentioned object, advantage and feature together with numerous other objects, advantages and features which will become evident from below detailed description of a preferred embodiment of the present invention is according to a first aspect of the present invention obtained by a method of processing a food product in particular fish in a food processing unit defining an interior space having an ambient temperature and a relative humidity controllable by said food processing unit and comprising following steps:
(a) thawing of said food product during a thawing period by inserting said food product in said interior space of said food processing unit and ejecting steam and water into said interior space while continuously re-circulating air within said interior space so as to increase said ambient temperature to a first temperature and said relative humidity to a pre-set relative humidity value,
(b) cooking of said food product in said interior space of said food processing unit during a cooking period by firstly discontinuing ejecting water into said interior space while continuing ejecting steam into said interior space so as to increase said ambient temperature from said first temperature to a second temperature, and secondly as said ambient temperature reaches said second temperature recirculating air within said interior space to maintain said ambient temperature at said second temperature,
(c) cooling of said food product in said interior space of said food processing unit during a cooling period by discontinuing ejecting steam into said interior space while ejecting water into said interior space and continuously re-circulating exterior air within said interior space communicated from outside of said interior space so as to decrease said ambient temperature to a third temperature, and
(d) calibrating said food processing unit by determining duration of said thawing period, duration of said cooking period and duration of said cooling period by utilising temperature sensitive means measuring a core temperature of said food product and establishing said duration of said thawing period, duration of said cooking period and said duration of cooling period according to said core temperature of said food product so as to terminate said thawing when said core temperature reaches a predetermined first core temperature, terminate said cooking when said core temperature reaches a predetermined second core temperature and terminate said cooling when said core temperature reaches a predetermined third core temperature,
so as to establish an interior environment in said interior space enabling energy transfer between said food product and said interior environment while limiting dehydration of said food product.
According to the realisation of the first aspect of the present invention the method provides thawing, cooking and cooling of a food product while continuously monitoring the conditions of the interior space of the food processing unit. Thus providing a very accurately controlled environment in the interior space optimised for the food product to be processed. Further the method according to the first aspect of the present invention ensures that energy consumption caused by heating the interior space is kept to a minimum by utilising the conditions of a previous process environment to establish a following process environment in the interior space. Thus thawing, cooking and cooling is performed as a continuous sequence so as to achieve low energy consumption of said food processing unit.
The food product may according to the first aspect of the present invention comprise a plurality of diary products, vegetable products, fruit products. poultry products, meat products, fish products or any combinations thereof. Any product may be processed utilising the food processing unit to provide the best possible processing of that particular food product. The first aspect of the present invention may be configured to provide processing in accordance to any particular food product and will enable a user to easily conform to any desired processing.
In accordance with above described feature the first aspect of the present invention provides for the interior space of the food processing unit to define a single compartment for receiving the food product and for sequentially performing the thawing, the cooking and the cooling of the food product, or to define a plurality of compartments for sequentially receiving the food product and for performing the thawing, the cooking and the cooling of the food product in separate compartments. By implementing the first aspect of the present invention having a single compartment or a plurality of compartments all the processes may be performed in a single compartment allowing for a highly accurate food processing. And by implementing the first aspect of the present invention having a plurality of compartments each performing a separate process on the food product a very efficient process may be achieved.
The first aspect of the present invention may have a preset relative humidity value defined n a relative humidity range between 80% and 100% such as between 90% and 100% or 95% and 100%. Preferably the relative humidity during the thawing is 100%. The first temperature is defined in a temperature range between 30xc2x0 C. and 50xc2x0 C. such as between 35xc2x0 C. and 40xc2x0 C, 40xc2x0 C. and 45xc2x0 C. or 45xc2x0 and 50xc2x0 C. Preferably the first temperature is approximately 38xc2x0 C. The second temperature is defined in a temperature range between 90xc2x0 C. and 100xc2x0 C. such as between 92xc2x0 C. and 98xc2x0 C. or 94xc2x0 C. and 96xc2x0 C. Preferably the second temperature is approximately 95xc2x0 C. Further the third temperature is defined in a temperature range between 15xc2x0 C. and 35xc2x0 C. such as between 20xc2x0 C. and 30xc2x0 C. or 24xc2x0 C. and 26xc2x0 C. Preferably the third temperature is approximately 25xc2x0 C. or equal to the exterior air temperature. All temperatures measured at normal atmospheric pressure. By selecting the first, second and third temperatures within the above mentioned temperature ranges in conjunction with accurately controlling the relative humidity of the interior of the food processing unit a significantly improved thawing is achieved avoiding unnecessary oxidation of the surfaces of the food products.
The first aspect of the present invention may further provide for having the predetermined first core temperature terminating the thawing period in a temperature range between xe2x88x925xc2x0 C. and +5xc2x0 C. such as ranges xe2x88x922xc2x0 C. to +2xc2x0 C. or xe2x88x921xc2x0 C. to +1xc2x0 C. Preferably the predetermined first core temperature terminates the thawing period when the temperature is approximately 0xc2x0 C. The predetermined second core temperature terminating the cooking period is in a temperature range between 40xc2x0 C. and 70xc2x0 C. such as ranges 45xc2x0 C. to 65xc2x0 C. or 50xc2x0 C. to 60xc2x0 C. Preferably the predetermined second core temperature is approximately 55xc2x0 C. The predetermined third core temperature terminating the cooling period is in a temperature range between 10xc2x0 C. and 40xc2x0 C. such as ranges 15xc2x0 C. to 35xc2x0 C. or 20xc2x0 C. to 30xc2x0 C. Preferably the predetermined third core temperature is approximately 25xc2x0 C. The predetermined first, second and third core temperatures are chosen on the basis of performing a series of test runs analysing a particular food products behaviour during the thawing, cooking and cooling process in the interior of the food processing unit. The test runs may be recorded and form the basis for further processing of that particular food product and the relevant temperature data stored in a data memory or database so that the predetermined temperature data for any tested food product easily may be utilised for following processing.
Further, in the first aspect of the present invention the thawing period is in a range between 20 and 500 minutes such as ranges 40 to 400 minutes or 80 to 200 minutes. The cooking period is in a range between 10 and 200 minutes such as ranges 20 to 150 minutes or 40 to 100 minutes. And the said cooling period is in a range between 40 and 400 minutes, such as ranges 60 to 300 minutes or 90 to 200 minutes. Any particular food product may have any duration of thawing, cooking and cooling depending on the texture and surface of the food product. By recording the temperature data as described above the timing data for any food product may correlated with the temperature data and thus monitoring of the temperature during subsequent processing of similar food products is rendered unnecessary since the ideal timing for the particular food product is known from the test runs.
Further, the first aspect of the present invention may comprise monitoring of air pressure in the interior space by utilising pressure sensor means measuring the air pressure and providing a pressure signal, and monitoring of the ambient temperature of the interior space by utilising interior temperature sensor means measuring the ambient temperature and providing a temperature signal. The first aspect of the present invention further controlling the air pressure and the ambient temperature of the interior space by utilising computing means receiving the pressure signal and the temperature signal during the thawing period, the cooking period and the cooling period by operating controllable valves ejecting steam and water into the interior space and by operating a controllable fan to re-circulated air within the interior space or to re-circulating exterior air within the interior space communicated from outside of the interior space. The first aspect of the present invention utilising computer means for controlling the air pressure and the ambient temperature of the interior space may provide for a detailed, accurate and repeatable control of the processing of food products. Computer means in this context should be construed as implemented by any form for processor techniques such as microcontroller technique, microprocessor technique, transputer technology, programmable logic devices or directly implemented by a custom design processor chip.
Above mentioned objects, advantages and features together with numerous other objects, advantages and features which will become evident from below detailed description of a further embodiment of the present Invention is according to a second aspect of the present invention obtained by a plant for processing food products in particular fish in a food processing unit defining an interior space having an ambient temperature and a relative humidity controllable by said food processing unit and comprising:
(a) a house for performing thawing of said food product during a thawing period by inserting said food product in an interior space of said house and ejecting steam and water into said interior space while continuously re-circulating air within said interior space so as to increase said ambient temperature to a first temperature and said relative humidity to a pre-set relative humidity value, for performing cooking of said food product in said interior space during a cooking period by firstly discontinuing ejecting water into said interior space while continuing ejecting steam into said interior space so as to increase said ambient temperature from said first temperature to a second temperature, and secondly as said ambient temperature reaches said second temperature re-circulating air within said interior space to maintain said ambient temperature at said second temperature, and for performing cooling of said food product in said interior space during a cooling period by discontinuing ejecting steam into said interior space while ejecting water into said interior space and continuously re-circulating exterior air within said interior space communicated from outside of said interior space so as to decrease said ambient temperature to a third temperature,
(b) steam generating means for generating and communicating steam to said interior space during said thawing and said cooking of said food product,
(c) sprinkling means for generating and communicating a water mist to said interior space during said thawing and said cooling of said food product,
(d) ventilating means for re-circulating air within said interior space and for circulating exterior air inside said interior space during said thawing, said cooking and said cooling of said food product,
(e) controllable valve means for controlling flow of steam and water to said steam generating means communicating steam to said interior space and to said sprinkling means communicating said water mist to said interior space,
(f) a control unit for controlling said steam generating means, said sprinkling means, said ventilating means and said controllable valve means during said thawing, said cooking and said cooling steps of said food processing unit and said control unit calibrated by determining duration of said thawing period, duration of said cooking period and duration of said cooling period by utilising temperature sensitive means measuring a core temperature of said food product and establishing said duration of said thawing period, duration of said cooking period and said duration of cooling period according to said core temperature of said food product so as to terminate said thawing when said core temperature reaches a predetermined first core temperature, terminate said cooking when said core temperature reaches a predetermined second core temperature and terminate said cooling when said core temperature reaches a predetermined third core temperature,
so as to establish an interior environment in said interior space enabling energy transfer between said food product and said interior environment while limiting dehydration of said food product.
In the basic realisation of the second aspect of the present invention the plant utilises the established temperatures and relative humidities during a process for further processing. Hence providing a plant that not only provides an environment for ensuring qualitative processing but also provides energy conservation.
The second aspect of the present invention further comprises all features of the first aspect of the present invention described above.
Above mentioned objects, advantages and features together with numerous other objects, advantages and features which will become evident from below detailed description of an alternative embodiment of the present invention is according to a third aspect of the present invention obtained by a plant for processing food products in particular fish in a food processing unit controlling ambient temperature and relative humidity within said food processing unit and comprising:
(a) a first house for performing thawing of said food product during a thawing period by inserting said food product in an first interior space of said house and ejecting steam and water into said first interior space while continuously re-circulating air within said interior space so as to maintain ambient temperature of said first interior space at a first temperature and relative humidity of said first interior space at a preset relative humidity value,
(b) a second house for performing cooking of said food product in a second interior space during a cooking period by inserting said food product in said second interior, ejecting steam into said second interior space and re-circulating air within said second interior space so as to maintain ambient temperature of said second interior space at a second temperature,
(c) a third house for performing cooling of said food product in a third interior space during a cooling period by inserting said food product in said third interior, ejecting water into said third interior space and continuously re-circulating exterior air within said third interior space communicated from outside of food processing unit so as to decrease ambient temperature to a third temperature,
(d) steam generating means for generating and communicating steam to said first and second interior spaces during said thawing and said cooking of said food product,
(e) sprinkling means for generating and communicating a water mist to said first and third interior spaces during said thawing and said cooling of said food product,
(f) ventilating means for recirculating air within said interior space and for circulating exterior air inside said first, second and third interior space during said thawing, said cooking and said cooling of said food product,
(g) controllable valve means for controlling flow of steam and water to said steam generating means communicating steam to said first and second interior spaces and to said sprinkling means communicating said water mist to said first and third interior spaces, and
(h) a control unit for controlling said steam generating means, said sprinkling means, said ventilating means and said controllable valve means during said thawing, said cooking and said cooling steps of said food processing unit and said control unit calibrated by determining duration of said thawing period, duration of said cooking period and duration of said cooling period by utilising temperature sensitive means measuring a core temperature of said food product and establishing said duration of said thawing period, duration of said cooking period and said duration of cooling period according to said core temperature of said food product so as to terminate said thawing when said core temperature reaches a predetermined first core temperature, terminate said cooking when said core temperature reaches a predetermined second core temperature and terminate said cooling when said core temperature reaches a predetermined third core temperature,
so as to establish an interior environment in said interior space enabling energy transfer between said food product and said interior environment while limiting dehydration of said food product.
In the basic realisation of the third aspect of the present invention the plant provides a qualitative food processing by ensuring the ideal temperatures and relative humidities during each processing step while maintaining a high efficiency.
The third aspect of the present invention further comprises all features of the first aspect and the second aspect of the present invention as described above and which will further be describe with reference to figures listed below.
FIG. 1 shows a time versus temperature graph for a fish weighing 2.6 kg processed according to state of the art thawing and cooking techniques.
FIG. 2 shows a time versus temperature graph for a fish weighing 2.2 kg processed according to a preferred embodiment of the present invention.
FIG. 3 shows a time versus temperature graph for a fish weighing 6.2 kg processed according to an alternative embodiment of the present invention.
FIG. 4 shows a three dimensional view of a processing station establishing an environment for performing processing of a product according to the preferred embodiment of the present invention.
FIG. 5 shows a cut away side view of the processing station establishing an environment for performing processing of a product according to the preferred embodiment of the present invention.
FIG. 6 shows a three dimensional view of a processing plant comprising a series of processing stations.
FIG. 7 shows a side view of an alternative processing plant comprising a series of processing stations each performing one operation.